1. Field of the Invention
The present invention relates to a telephone device and system using the device capable of transmitting and receiving information on telephone numbers together with voice information, and more particularly to improvements to the control function of the telephone device and system using the device capable of informing a party during telephonic communication that a third party has placed a call to the party, by using the information on the third party's telephone number sent together with the voice information.
2. Description of the Related Art
A service which allows an incoming call from a third party to be received by a first party during telephonic communication with a second party is known. For example, Nippon Telephone and Telegram Corporation (NTT) has been providing a service called "catchphone" as an additional function of telephone devices.
This service is achieved by a control process comprising
steps of informing, with a calling tone, a first party who has been talking to a second party that there is an incoming call from a third party, detecting that the first part has depressed a predetermined key, and switching the communication channel to the third party while holding the communication channel with the second party.
However, according to the conventional service of this type, even if it is informed that there is an incoming call from a third party during communication with the second party, the called (first) party cannot be informed who the third party is as long as the called party does not respond to the incoming call.
Therefore, the called party must respond to the incoming call to confirm who the caller is, and decide whether to continue the talk with the third party or say a simple message to the third party such as "I will call you later" and resume the communication with the second party.
If the third perry's incoming call involves an emergency matter or is made by an important person for the called party, it is advantageous to interrupt the ongoing telephonic communication with the second party so as to respond to the third party's call.
However, if the incoming call is not an important one, the interruption of the ongoing communication usually causes inconvenience.
In order to respond to the incoming call from the third party, the called party must switch the connection from party of ongoing communication (second party) to the third party, which would hinder smooth telephonic communication with the second party.
When the connection is switched to the third party, it is required to send an interrupting tone to the second party and to place the second party in a mute state during holding, which gives an uncomfortable feeling to the second party.
As described above, when the service function such as "catchphone" is utilized in the conventional telephone device, the called party cannot confirm who is the interrupting party unless the called party actually responds to the call. Therefore, the ongoing communication must be interrupted to switch the connection to the interrupting person even when the called party merely desires to confirm the name of the interrupting party, which gives an uncomfortable feeling to the party to whom the ongoing communication is being made.
Such uncomfortable feeling can be alleviated to some extent, for example, by making a short answer such as "I will call you later" to the third party and then resuming the ongoing communication immediately.
However, even if the incoming call from the third party is responded to in the above manner, it is necessary to find out the telephone number of the third party and to dial that number when calling is made to the third party later. It takes time to find out the telephone number and there is a possibility to wrong dialing. Thus, there is a case in which smooth access to the third party is difficult.